Substrate processing apparatus

ABSTRACT

A substrate processing apparatus comprises a substrate transfer chamber; a plurality of substrate processing chambers disposed on a first side wall of the substrate transfer chamber and stacked in the vertical direction; a plurality of first gate valves, each being disposed between each of the substrate processing chambers and the substrate transfer chamber; a substrate accommodating chamber disposed on a second side wall of the substrate transfer chamber; a substrate transfer device, disposed within the substrate transfer chamber, for transferring the substrate under reduced pressure between the substrate processing chambers and the substrate accommodating chamber; an elevator disposed outside the substrate transfer chamber and comprising a stationary portion and an elevating portion which is vertically movable with respect to the stationary portion; a rigid connecting member capable of moving through a through-hole formed in a predetermined face of the substrate transfer chamber, the rigid connecting member mechanically connecting the elevating portion and the substrate transfer device through the through-hole; and a sealing member for establishing a hermetic vacuum seal between the predetermined surface and the connecting member which penetrates through the through-hole.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a substrate processing apparatus, andparticularly to a semiconductor wafer processing apparatus.

2. Description of the Related Art

Conventionally, in order to reduce the area occupied by a semiconductorwafer processing apparatus, a semiconductor wafer processing apparatusas shown in FIG. 1 (Refer to Japanese Patent Application Laid-Open No.5-152215.) is proposed.

In a semiconductor wafer processing apparatus 2000 of FIG. 1, aplurality of reaction chambers 204 are arranged in layers perpendicularto an installation floor, thereby reducing the floor area occupied bythe semiconductor wafer processing apparatus 2000.

In the semiconductor wafer processing apparatus 2000, a wafer transferrobot 202 and a robot elevator 201 for hoisting and lowering the robot202 are disposed within a wafer transfer chamber 205. The robot elevator201 hoists and lowers the wafer transfer robot 202 so as to load asemiconductor wafer into or unload from a reaction chamber 204 through agate valve 203.

As described above, in the conventional semiconductor wafer processingapparatus 2000, since the robot elevator 201 is disposed within thewafer transfer chamber 205, the interior of the wafer transfer chamber205 is contaminated and consequently the interior of the reactionchamber 204 is contaminated, resulting in contamination of a waferprocessed by the semiconductor wafer processing apparatus 2000 and thusintroducing a problem of poor yield in production of semiconductordevices.

SUMMARY OF THE INVENTION

In view of the foregoing, it is a main object of the present inventionto provide a substrate processing apparatus capable of preventing theinterior thereof from being contaminated due to a elevator or the like.

According to the present invention, there is provided a substrateprocessing apparatus, comprising:

a substrate transfer chamber which can be depressurized;

a plurality of substrate processing chambers disposed on a first sidewall of the substrate transfer chamber, the plurality of substrateprocessing chambers being stacked in the vertical direction;

a plurality of first valves, each being disposed between each of thesubstrate processing chambers and the substrate transfer chamber, andeach of the plurality of the first valves being capable of providinghermetic vacuum isolation between each of the substrate processingchambers and the substrate transfer chamber when closed and allowing asubstrate to pass therethrough when opened; a substrate accommodatingchamber disposed on a second side wall of the substrate transferchamber;

a substrate transfer device disposed within the substrate transferchamber and being capable of transferring the substrate under reducedpressure between the substrate processing chambers and the substrateaccommodating chamber;

elevating means disposed outside the substrate transfer chamber andcomprising a stationary portion and an elevating portion which isvertically movable with respect to the stationary portion;

a rigid connecting member capable of moving through a through-holeformed in a predetermined face of the substrate transfer chamber, therigid connecting member mechanically connecting the elevating portionand the substrate transfer device through the through-hole; and

a sealing member for establishing a hermetic vacuum seal between thepredetermined face and the connecting member which penetrates throughthe through-hole.

In the present invention, since the elevating means is disposed outsidethe substrate transfer chamber, the interior of the substrate transferchamber can be prevented from being otherwise contaminated due to thepresence of the elevating means, thereby preventing substrates frombeing contaminated.

Since the elevating portion of the elevating means and the substratetransfer device are mechanically connected, through the through-hole, bythe rigid connecting member which can move through the through-holeformed in the predetermined face of the substrate transfer chamber, eventhough the elevating means is disposed outside the substrate transferchamber, the substrate transfer device can be reliably elevated andlowered by the elevating means.

In order to connect the elevating portion and the substrate transferdevice via a predetermined face of the substrate transfer chamber suchthat the substrate transfer device goes up/down as the elevating portiongoes up/down, the elevating portion and the substrate transfer devicemay be magnetically coupled. In this case, there is no need for forminga through-hole in a predetermined face of the substrate transferchamber, but the predetermined face may be made of material which allowsthe transmission of magnetic lines of force, thereby magneticallyconnecting the elevating portion and the substrate transfer device whichare isolated from each other by the face.

Since there is disposed the sealing member for establishing a hermeticvacuum seal between the predetermined face of the substrate transferchamber and the connecting member which penetrates through thethrough-hole formed in the predetermined face, even though thethrough-hole is formed in the predetermined face of the substratetransfer chamber and the substrate transfer device is adapted by therigid connecting member to go up/down as the elevating portion goesup/down, the substrate transfer chamber can be hermeticallyvacuum-sealed and can be depressurized.

Further, since the plurality of substrate processing chambers aredisposed on the first side wall of the substrate transfer chamber andare stacked in the vertical direction, the area occupied by thesubstrate processing chambers can be reduced within a clean room. Also,the number of sides of the substrate transfer chamber can be reducedthereby to reduce the size of the substrate transfer chamber, resultingin a reduction in the area occupied by the substrate transfer chamber.Thus, the substrate processing apparatus occupies less area within theclean room.

As the number of sides of the substrate transfer chamber is reduced, thecost of manufacture of the substrate transfer chamber can be reduced,and the required multidirectional maintenance space can also be reduced.Further, in the case where the substrate transfer chamber is connectedto another substrate transfer chamber or the like, the distance overwhich a connection is made between the substrate transfer chamber andanother substrate transfer chamber or the like can be reduced. Thisallows a substrate to be transferred between the substrate transferchamber and another substrate transfer chamber or the like withoutproviding a substrate transfer device at a connecting sectiontherebetween; thus the substrate processing apparatus can accordingly bemade simpler in structure and manufactured at lower cost.

Since there are provided the plurality of first valves, each beinglocated between each of the substrate processing chambers and thesubstrate transfer chamber, and each of the plurality of the firstvalves is capable of providing hermetic vacuum isolation between each ofthe substrate processing chambers and the substrate transfer chamberwhen closed and allowing a substrate to pass therethrough when opened,each substrate processing chamber and the substrate transfer chamber canbe maintained under vacuum independently of each other, and also asubstrate can move between each substrate processing chamber and thesubstrate transfer chamber. This first valve is preferably a gate valve.

A substrate is preferably a semiconductor wafer. In this case, thesubstrate processing apparatus functions as a semiconductor waferprocessing apparatus.

A substrate may also be a glass substrate for use in a liquid crystaldisplay device.

In the substrate processing chamber, there are preferably performedprocesses including: the deposition of various films, includinginsulating films, metal wiring films, polycrystalline silicon films, andamorphous silicon films, by various CVD (Chemical Vapor Deposition)methods such as a plasma enhanced CVD method, a hot wall CVD method, aphoto assisted CVD method and the like; etching; heat treatment such asannealing and the like; epitaxial growth; and diffusion.

The substrate transfer device is preferably a substrate transfer devicefor transferring a substrate in a horizontal direction, more preferablyan articulated robot.

Preferably, the sealing member is formed of an elastic material andcovers the rigid connecting member, which connects the elevating portionand the substrate transfer device, such that the connecting member canmove within the sealing member and that one end of the sealing member isconnected in a hermetically vacuum-sealed manner to the predeterminedface of the substrate transfer chamber while the other end of thesealing member is connected in a hermetically vacuum-sealed manner tothe connecting member. Since hermetic vacuum seal is maintained by theelastic material, the maintenance of hermetic vacuum seal is reliableand the movement of the connecting member can be handled independentlyof the maintenance of the hermetic vacuum seal, thereby ensuring thesmooth, reliable movement of the connecting member. The description "oneend of the sealing member is connected in a hermetically vacuum-sealedmanner to the predetermined face of the substrate transfer chamber"encompasses both the case where one end of the sealing member isconnected in a hermetically vacuum sealed manner directly to thepredetermined face of the substrate transfer chamber, and the case whereone end of the sealing member is connected in a hermeticallyvacuum-sealed manner indirectly to the predetermined face of thesubstrate transfer chamber via another member. Similarly, thedescription "the other end of the sealing member is connected in ahermetically vacuum-sealed manner to the connecting member" encompassesboth the case where the other end of the sealing member is connected ina hermetically vacuum-sealed manner directly to the connecting memberand the case where the other end of the sealing member is connected in ahermetically vacuum-sealed manner indirectly to the connecting membervia another member.

The sealing member formed of an elastic material is preferably bellows,more preferably metallic bellows.

The sealing member may be an O-ring. By installing an O-ring between thethrough-hole and the connecting member, both the maintenance of hermeticvacuum seal and the movement of the connecting member can be ensured ina simple structure.

Preferably, the stationary portion of the elevating means is a screwshaft, and the elevating portion comprises a nut, thereby forming a ballscrew by the screw shaft and the nut. The ball screw provides smallerfriction and higher mechanical efficiency.

Preferably, the predetermined face of the substrate transfer chamberwhere the through-hole is formed is the bottom face of the substratetransfer chamber, and the ball screw is located under the substratetransfer chamber. This prevents the interior of the substrate transferchamber from being contaminated with particles generated from thesealing member such as bellows.

This predetermined face of the substrate transfer chamber may be the topface of the substrate transfer chamber, and the ball screw may belocated above the substrate transfer chamber.

Preferably, the substrate transfer device comprises a driving unit, asubstrate transfer unit capable of moving in a substantially horizontaldirection by the driving unit, and a driving unit container capable ofproviding hermetic vacuum isolation between the inside and outside ofthe driving unit container, and the driving unit is accommodated in thedriving unit container, thereby maintaining the clean atmosphere withinthe substrate transfer chamber.

In this case, one end portion of the rigid connecting member ispreferably connected to the driving unit container at the vicinity of anend portion thereof located closer to the substrate transfer unit. Thus,the height of the substrate processing apparatus as a whole can bereduced.

Preferably, in a case where the predetermined face of the substratetransfer chamber where the through-hole is formed is either the bottomface or the top face of the substrate transfer chamber, a projectingsection whose shape corresponds to the driving unit container isprojected from the bottom face when the predetermined face is the bottomface, or from the top face when the predetermined face is the top face,such that the projecting section is capable of accommodating the drivingunit container therein. Since in order to accommodate the driving unitcontainer, only the projecting section is projected from the wafertransfer chamber without increasing the entire size of the wafertransfer chamber, the volume of the wafer transfer chamber can bereduced, thereby reducing time required for evacuating the wafertransfer chamber.

Preferably, the predetermined face of the substrate transfer chamber isthe bottom face of the substrate transfer chamber.

Preferably, a second valve is disposed between the substrateaccommodating chamber and the substrate transfer chamber, and the secondvalve is capable of providing hermetic vacuum isolation between thesubstrate accommodating chamber and the substrate transfer chamber whenclosed and allowing a substrate to pass therethrough when opened,thereby allowing the substrate accommodating chamber to be depressurizedindependently of the substrate transfer chamber.

By allowing the substrate transfer chamber and the substrateaccommodating chamber to be depressurized, the oxygen concentrationtherein can be reduced to a minimal level, thereby suppressing oxidationof a substrate in the substrate transfer chamber and the substrateaccommodating chamber.

The second valve is disposed between the substrate transfer chamber andthe substrate accommodating chamber, and the second valve is capable ofproviding hermetic vacuum isolation between the substrate transferchamber and the substrate accommodating chamber when closed and allowingthe substrate to pass therethrough when opened. Therefore the substratetransfer chamber and the substrate accommodating chamber can bemaintained under vacuum independently of each other, and also asubstrate can move between the substrate transfer chamber and thesubstrate accommodating chamber. This second valve is preferably a gatevalve.

Further, the substrate processing apparatus according to the presentinvention preferably comprises an atmospheric pressure section locatedat a side which is different from the substrate transfer chamber's sidewith respect to the substrate accommodating chamber, and a third valvedisposed between the substrate accommodating chamber and the atmosphericpressure section, the third valve being capable of maintaining thesubstrate accommodating chamber under vacuum in isolation from theatmospheric pressure section when closed and allowing a substrate topass therethrough when opened.

Thus, the substrate accommodating chamber can be maintained under vacuumin isolation from the atmospheric pressure section, and also a substratecan move between the substrate accommodating chamber and the atmosphericpressure section.

As described above, since the second and third valves are disposed atthe substrate accommodating chamber and the substrate accommodatingchamber can be depressurized independently of the substrate transferchamber, the substrate accommodating chamber can function as a load-lockchamber when a substrate is transferred between the atmospheric pressuresection and the substrate transfer chamber maintained under reducedpressure.

Preferably, heat resistant first substrate holding means is disposedwithin the substrate accommodating chamber, whereby the substrateaccommodating chamber can be used as a substrate cooling chamber forcooling a high-temperature substrate which has been processed in thesubstrate processing chamber.

The heat resistant first substrate holding means is preferably a heatresistant substrate holder made of quartz, glass, ceramics, or metal,whereby even when the substrate accommodating chamber is maintainedunder vacuum, impurities such as outgass are not generated from thesubstrate holder, thereby maintaining clean the atmosphere within thesubstrate accommodating chamber. Ceramics are preferably sintered SiC,or sintered SiC coated with SiO₂ by CVD or the like.

As described above, since the substrate accommodating chamber can beused as a substrate cooling chamber and as a load-lock chamber, there isno need for providing a substrate cooling chamber and a cassette chamberon side walls of the substrate transfer chamber, and a cassette can beplaced in the atmospheric pressure section.

Since the second valve is disposed between the substrate transferchamber and the substrate accommodating chamber, the pressure of thesubstrate accommodating chamber can be restored to atmospheric pressurewhile the substrate transfer chamber is maintained under reducedpressure, and a substrate contained in the substrate accommodatingchamber naturally cools down while the pressure of the substrateaccommodating chamber is being restored to atmospheric pressure, so thatthe temperature of each substrate is lowered to a sufficient levelbefore the substrate leaves the substrate accommodating chamber.Consequently, when the substrate is subsequently taken out intoatmospheric environment, it can be prevented from being oxidized orcontaminated by atmospheric environment. In this manner, a step ofrestoring pressure to atmospheric pressure and a step of cooling asubstrate can be simultaneously performed within the substrateaccommodating chamber, and subsequently the cooled substrate can betransferred under atmospheric pressure to a cassette. A cassette whichcontains substrates can then be delivered out from the substrateprocessing apparatus.

Preferably, a plurality of substrate accommodating chambers are disposedon the second side wall of the substrate transfer chamber, the pluralityof the substrate accommodating chambers being stacked in the verticaldirection, and there are disposed a plurality of fourth valves, eachbeing located between each of the substrate accommodating chambers andthe substrate transfer chamber and being capable of providing hermeticvacuum isolation between each of the substrate accommodating chambersand the substrate transfer chamber when closed and allowing thesubstrate to pass therethrough when opened, whereby the substrateaccommodating chambers can be depressurized independently of one anotherand each of the substrate accommodating chambers can be depressurizedindependently of the substrate transfer chamber. This fourth valve ispreferably a gate valve.

By providing a plurality of substrate accommodating chambers on a sidewall of the substrate transfer chamber, while a certain substrateaccommodating chamber is used for cooling a substrate contained therein,another substrate accommodating chamber may be used for transferring asubstrate to the substrate processing chamber, thereby saving time.

Since a plurality of substrate accommodating chambers are disposed onthe second side wall of the substrate transfer chamber, such that theplurality of the substrate accommodating chambers are stacked in thevertical direction, the area occupied by the substrate accommodatingchambers can be reduced within a clean room. Also, the number of sidesof the substrate transfer chamber can be reduced thereby to reduce thesize of the substrate transfer chamber, resulting in a reduction in thearea occupied by the substrate transfer chamber. Thus, the substrateprocessing apparatus occupies less area within the clean room.

As the number of sides of the substrate transfer chamber is reduced, thecost of manufacture of the substrate transfer chamber is reduced, andthe required multidirectional maintenance space is also reduced.Further, when a plurality of substrate processing apparatuses aredisposed, the distance over which a connection is made between thesubstrate transfer chamber and another substrate transfer chamber or thelike can be reduced. This allows a substrate to be transferred betweenthe substrate transfer chamber and another substrate transfer chamber orthe like without providing a substrate transfer device at a connectingsection therebetween; thus the substrate processing apparatus canaccordingly be made simpler in structure and manufactured at lower cost.Further, the maintenance space for one substrate processing apparatusdoes not interfere with that for another substrate processing apparatus;therefore a plurality of substrate processing apparatuses can beefficiently arranged.

Two kinds of substrate accommodating chambers, one for incomingsubstrates and the other for outgoing substrates, may be separatelyprovided. This allows two kinds of substrate accommodating chambers tobe alternately used, thereby saving time.

Preferably, there are further disposed cassette holding means locatedwithin the atmospheric pressure section, and substrate transfer meanslocated within the atmospheric pressure section and capable oftransferring a substrate between a cassette held by the cassette holdingmeans and the substrate accommodating chamber.

By disposing within the atmospheric pressure section the cassetteholding means and the substrate transfer means capable of transferring asubstrate between a cassette held by the cassette holding means and thesubstrate accommodating chamber, the cassette holding means and thesubstrate transfer means can be made simpler in structure as comparedwith the case where they are disposed in a vacuum environment.

A cassette is preferably a cassette for carrying substrates in and/orcarrying them out from the substrate processing apparatus.

Preferably, a housing is further provided for accommodating thesubstrate processing chamber, the substrate transfer chamber, thesubstrate accommodating chamber, the substrate transfer means, and thecassette holding means. By disposing the substrate transfer means andthe cassette holding means within the housing, the surface of asubstrate placed in a cassette and the surface of a substrate beingtransferred by the substrate transfer means can be maintained clean.

Preferably, the substrate processing apparatus of the present inventionhas the following structure. A housing is further provided foraccommodating at least the substrate transfer chamber, the plurality ofsubstrate processing chambers, and the substrate accommodating chamber.At least each part of each of the projecting section of the substratetransfer chamber, the elevating means and the connecting member isprojected from the housing. Such a housing provides the followingadvantage in addition to a reduction in particles within the substrateprocessing apparatus. By projecting from the housing at least each partof each of the projecting section of the substrate transfer chamber, theelevating means and the connecting member, at least each part of each ofthe projecting section of the substrate transfer chamber, the elevatingmeans and the connecting member can be projected downward from the floorof a clean room or upward from the ceiling of the clean room. As aresult, the substrate transfer chamber, the plurality of substrateprocessing chambers arranged in layers, and the substrate accommodatingchamber can be increased in height, thereby increasing their capacity ofaccommodating substrates and thus increasing the number of substrates tobe processed at one time.

Preferably, the substrate processing apparatus of the present inventionhas the following structure. There are further provided first substrateholding means, disposed within the substrate accommodating chamber, forholding a substrate and second substrate holding means, disposed withinthe substrate processing chamber, for holding a substrate. The secondsubstrate holding means can hold a plurality of substrates, the firstsubstrate holding means can hold a plurality of substrates, and thepitch of substrates held by the first substrate holding means issubstantially identical to that of substrates held by the secondsubstrate holding means.

In this case, more preferably, the substrate transfer means can transfera plurality of substrates at one time and can also change the pitch ofthe substrates.

Since the second substrate holding means disposed within the substrateprocessing chamber can hold a plurality of substrates, the substratescan be processed in the substrate processing chamber with an increasedefficiency.

Since the first substrate holding means disposed within the substrateaccommodating chamber can hold a plurality of substrates and the pitchof substrates held by the first substrate holding means is substantiallyidentical to that of substrates held by the second substrate holdingmeans, the structure of the substrate transfer device, disposed withinthe substrate transfer chamber, which can be depressurized, can besimplified. Preferably, the substrate transfer device can transfer aplurality of substrates at one time under reduced pressure.

By making the pitch of substrates held by the first substrate holdingmeans substantially identical to that of substrates held by the secondsubstrate holding means, even when the substrate transfer device adoptsthe structure capable of transferring a plurality of substrates at onetime under reduced pressure, there is no need for changing the pitch ofsubstrates while transferring substrates. As a result, the structure ofthe substrate transfer device becomes simple, and contamination ofvacuum can be prevented. Further, since a plurality of substrates can betransferred at one time, the efficiency of transferring substratesincreases.

By contrast, if the pitch of substrates is made variable under reducedpressure, the structure of a transfer device will become complicated,and more than twice as much cost and space will be required as comparedwith the use of the transfer device under atmospheric pressure.Moreover, due to an increase in the number of mechanisms, contaminantsgenerated from a driving shaft and the like become more likely toscatter. This results in a failure to maintain a predetermined degree ofvacuum and is likely to introduce a problem of particles and to causecontamination of a substrate. Since particles are generated, within thesubstrate transfer chamber, located adjacent to the substrate processingchamber, the effect of particles is particularly large. If in order toavoid such a problem, substrates are transferred one by one between thefirst substrate holding means and the second substrate holding means,throughput will deteriorate. If in order to improve throughput, thetransferring speed of a substrate transfer device is increased, thenumber of operations per unit time of the substrate transfer device willincrease, resulting in a decrease in service life of the apparatus andintroduction of a problem of particles.

In order to concurrently process, for example, to concurrently deposit afilm on a plurality of substrates within the substrate processingchamber, these substrates must be arranged not at the pitch of groovesin a cassette, but at a pitch which is determined in consideration of agas flow and the like within the substrate processing chamber, so as tomaintain uniformity of a film thickness and the like. Therefore, it ispreferable that the pitch of substrates is changed from the pitch of thegrooves of the cassette at a certain point of transfer of substrates.

In the present invention, the substrate transfer means preferably has astructure capable of transferring a plurality of substrates at one timeand changing the pitch of these substrates. Since the substrate transfermeans is used under atmospheric pressure, even when the pitch ofsubstrates is made variable, the substrate transfer means is simpler instructure and can be manufactured at lower cost as compared with thatfor use under vacuum, and the generation of particles can be suppressed.

By adopting the above-mentioned method of transferring a plurality ofsubstrates at one time while the pitch of substrates is variable duringtransfer under atmospheric pressure and fixed during transfer underreduced pressure, the cost of manufacture of transfer devices can bereduced, the size of the transfer devices can be reduced, and thegeneration of particles can be suppressed so as to provide a cleanenvironment for transfer of substrates. Further, since a plurality ofsubstrates are transferred at one time, throughput improves. Since thepitch of substrates is variable, the pitch can be changed so as toprocess substrates at high precision within the substrate processingchamber.

Preferably, the first substrate holding means can hold at least twice asmany substrates as those to be processed at one time within each of thesubstrate processing chambers.

Preferably, the first substrate holding means can hold at least twice asmany substrates as those to be held by the second substrate holdingmeans, whereby the first substrate holding means can hold at least twiceas many substrates as those to be processed at one time within each ofthe substrate processing chambers.

As a result, substrates can be efficiently transferred between thesubstrate processing chamber and a cassette, thereby improvingthroughput.

Preferably, the first and second side walls of the substrate transferchamber are opposed to each other so as to arrange on a substantiallystraight line the substrate processing chamber, the substrate transferchamber, and the substrate accommodating chamber. This minimizes thenumber of sides of the substrate transfer chamber; for example, thesubstrate transfer chamber may assume a rectangular shape.

Preferably, the substrate transfer chamber has a rectangular shape asviewed from above, thereby reducing the size of the substrate transferchamber and thus reducing the area occupied by the substrate transferchamber. Thus, the substrate processing apparatus occupies less areawithin a clean room. By adopting the rectangular shape, the cost ofmanufacture of the substrate transfer chamber is reduced, and a requiredmaintenance space is also reduced. Further, the distance over which aconnection is made between the substrate transfer chamber and anothersubstrate transfer chamber or the like can be reduced. This allows asubstrate to be readily transferred between the substrate transferchamber and another substrate transfer chamber or the like withoutproviding a substrate transfer device at a connecting sectiontherebetween; thus the substrate processing apparatus can accordingly bemade simpler in structure and manufactured at lower cost. A plurality ofsubstrate processing units, each having the structure such that thesubstrate processing chamber, the substrate transfer chamber, and thesubstrate accommodating chamber are arranged on a substantially straightline, can be readily arranged in parallel so that they occupy less area.

Preferably, the cassette holding means is located opposite to thesubstrate transfer chamber with respect to the substrate accommodatingchamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription taken in conjunction with the accompanying drawings,wherein:

FIG. 1 is a cross sectional view for explaining a conventionalsemiconductor wafer processing apparatus;

FIG. 2 is a plan view for explaining a semiconductor wafer processingapparatus according to a first embodiment of the present invention;

FIG. 3 is a cross-sectional view taken along the line X--X in FIG. 2;

FIG. 4 is a schematic perspective view for explaining a wafer holder foruse in the first through seventh embodiments of the present invention;

FIGS. 5A and 5B are schematic perspective views for explaining awafer-transfer vacuum robot for use in the first through seventhembodiments of the present invention;

FIG. 6 is a schematic perspective view for explaining a cassettetransfer and wafer transfer device for use in the first through seventhembodiments of the present invention;

FIG. 7A is a side view for explaining a pitch changing mechanism of thecassette transfer and wafer transfer device for use in the first throughseventh embodiments of the present invention;

FIG. 7B is a rear view taken along the line Y--Y in FIG. 7A;

FIG. 8 is a schematic cross-sectional view for explaining the operationof transferring wafers in the semiconductor processing apparatusaccording to the first embodiment;

FIG. 9 is a cross-sectional view for explaining a semiconductor waferprocessing apparatus according to a second embodiment of the presentinvention;

FIG. 10 is a cross-sectional view for explaining a semiconductor waferprocessing apparatus according to a third embodiment of the presentinvention;

FIG. 11 is a plan view for explaining a semiconductor wafer processingapparatus according to a fourth embodiment of the present invention;

FIG. 12 is a plan view for explaining a semiconductor wafer processingapparatus according to a fifth embodiment of the present invention;

FIG. 13 is a plan view for explaining a semiconductor wafer processingapparatus according to a sixth embodiment of the present invention; and

FIG. 14 is a plan view for explaining a semiconductor wafer processingapparatus according to a seventh embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment:

FIG. 2 is a plan view for explaining a semiconductor wafer processingapparatus according to a first embodiment of the present invention. FIG.3 shows a cross-sectional view taken along the line X--X in FIG. 2.

A semiconductor wafer processing apparatus 1 of the present embodimentis composed of a processing section 700, a transfer section 500, and afront section 100.

The processing section 700 is composed of a plurality of processingmodules 701, each including a reaction chamber 70 and a gate valve 93.The transfer section 500 is composed of a transfer module 501, whichincludes a wafer transfer chamber 50 and a wafer-transfer vacuum robot60. The front section 100 is composed of a plurality of load-lockmodules 300 and an atmospheric pressure section 200. Each load-lockmodule 300 is composed of an wafer accommodating chamber 30, a gatevalve 92, and a front door valve 91. In the atmospheric pressure section200, there are disposed cassette shelves 11, each being used formounting a cassette 10 thereon, and a cassette transfer and wafertransfer device 20.

The plurality of reaction chambers 70 are arranged in the verticaldirection and connected to a wall 53 of the wafer transfer chamber 50.The gate valve 93 is disposed between each reaction chamber 70 and thewafer transfer chamber 50. Each reaction chamber 70 is adapted to beindependently evacuated via an exhaust pipe 82. Within each reactionchamber 70 is placed a wafer boat 75 capable of carrying a plurality of(two in the present embodiment) semiconductor wafers 5 so as to processa plurality of wafers 5 at one time, thereby increasing the waferprocessing efficiency. The pitch of wafers 5 carried in the wafer boat75 is determined in consideration of a gas flow and the like within thereaction chamber 70; for example, when a process of depositing a film isto be performed within the reaction chamber 70, the pitch is determinedso as to maintain the uniformity of film thickness within apredetermined range.

In the reaction chamber 70 there are performed processes including: thedeposition of various films, including insulating films, metal wiringfilms, polycrystalline silicon films, and amorphous silicon films, byvarious kinds of CVD such as plasma enhanced CVD, hot wall CVD, photoassisted CVD, and the like; etching; heat treatment such as annealingand the like; epitaxial growth; diffusion.

Since the plurality of reaction chambers 70 are disposed in verticallayers on the wall 53 of the wafer transfer chamber 50, the areaoccupied by the reaction chambers 70 within a clean room can be reduced.Also, the number of sides of the wafer transfer chamber 50 can bereduced thereby to reduce the size of the wafer transfer chamber 50,resulting in a reduction in the area occupied by the wafer transferchamber 50. Thus, the semiconductor wafer processing apparatus 1occupies less area within the clean room.

As the number of sides of the wafer transfer chamber 50 is reduced, thecost of manufacture of the wafer transfer chamber 50 is reduced, and therequired multidirectional maintenance space is also reduced. Further, inthe case where another wafer transfer chamber is connected to the wafertransfer chamber 50, the distance between the wafer transfer chamber 50and another wafer transfer chamber or the like can be reduced. Thisallows a wafer to be transferred between the wafer transfer chamber 50and another wafer transfer chamber or the like without providing a wafertransfer device at a connecting section therebetween; thus thesemiconductor wafer processing apparatus 1 can accordingly be madesimpler in structure and manufactured at lower cost.

The plurality of wafer accommodating chambers 30 are disposed invertical layers on a wall 54 of the wafer transfer chamber 50. The gatevalve 92 is disposed between each wafer accommodating chamber 30 and thewafer transfer chamber 50. The front door valve 91 is disposed betweeneach wafer accommodating chamber 30 and the atmospheric pressure section200. Each wafer accommodating chamber 30 is adapted to be independentlyevacuated via exhaust pipes 83 and 81.

A wafer holder 40 is placed within the wafer accommodating chamber 30.FIG. 4 is a schematic perspective view for explaining the wafer holder40. The wafer holder 40 has upper and lower disk-like column supportingplates 41 and 42 and two prismatic columns 43 and 44, which are heldbetween the plates 41 and 42. A plurality of wafer supporting grooves 45are formed in each of the columns 43 and 44, and the columns 43 and 44stand such that respective grooves 45 face each other. The both ends ofthe grooves 45 are open so as to allow wafers to be loaded from bothsides of the wafer holder 40 and to be unloaded to both sides thereof.The wafer holder 40 is made of quartz.

The pitch of the wafer supporting grooves 45 of the wafer holder 40,i.e. the pitch of wafers 5 held in the wafer holder 40 is made equal tothat of wafers 5 mounted in the wafer boat 75 in the reaction chamber70. The pitch of the wafer supporting grooves 45 of the wafer holder 40is larger than that of grooves for holding wafers within the cassette10.

The number of the wafer supporting grooves 45 of the wafer holder 40,i.e. the number of wafers 5 which the wafer holder 40 can hold is atleast twice the number of wafers 5 which the wafer boat 75 within thereaction chamber 70 can carry, i.e. at least twice the number of wafers5 which can be processed at one time within the reaction chamber 70.Thus, the wafers 5 can be efficiently transferred between the reactionchamber 70 and the cassette 10, resulting in improved throughput.

Since the wafer holder 40 is made of quartz, even when the waferaccommodating chamber 30 is maintained under vacuum, impurities are notoutgassed from the wafer holder 40, thereby maintaining clean theatmosphere within the wafer accommodating chamber 30.

Since the wafer holder 40 is made of quartz and thus has excellent heatresistance, the high-temperature wafer 5 which has been processed in thereaction chamber 70 can be cooled while being held in the wafer holder40. The wafer holder 40 can thus be used for cooling wafers 5, so thatthe wafer accommodating chamber 30 functions as a wafer cooling chamber.Accordingly, there is no need for providing a separate cooling chamberon a side wall of the wafer transfer chamber 50 in order to cool thehigh-temperature wafer 5 which has been processed in the reactionchamber 70, whereby the area occupied by the semiconductor waferprocessing apparatus 1 within a clean room can be reduced by the areawhich would otherwise be occupied by the cooling chamber. Also, thenumber of sides of the wafer transfer chamber 50 can be reduced therebyto reduce the size of the wafer transfer chamber 50, resulting in areduction in the area occupied by the wafer transfer chamber 50. Thus,the semiconductor wafer processing apparatus 1 occupies less area withinthe clean room. Further, the cost of manufacture of the wafer transferchamber 50 can be reduced.

Since the wafer holder 40 temporarily accommodates wafers 5 on the wayof transfer from the cassette 10 to the wafer processing chamber 70,temporarily accommodates wafers 5 on the way of transfer from the waferprocessing chamber 70 to the cassette 10, or temporarily accommodateswafers 5 on the way of transfer from the cassette 10 to the waferprocessing chamber 70 as well as wafers 5 on the way of transfer fromthe wafer processing chamber 70 to the cassette 10, there is no need forproviding a cassette chamber for accommodating the cassette 10 on a sidewall of the wafer transfer chamber 50. As a result, the number ofchambers to be disposed on side walls of the wall transfer chamber 50 isreduced, and the area occupied by the wafer processing apparatus 1within a clean room can be reduced accordingly. Further, the number ofsides of the wafer transfer chamber 50 is reduced, and the size of thewafer transfer chamber 50 is reduced accordingly, resulting in adecrease in the area occupied by the wafer transfer chamber 50. Thisalso reduces the area occupied by the semiconductor wafer processingapparatus 1 within the clean room. Further, the cost of manufacture ofthe wafer transfer chamber 50 is reduced.

In the present embodiment, since the plurality of wafer accommodatingchambers 30 are disposed on the wall 54 of the wafer transfer chamber50, while a certain wafer accommodating chamber 30 is used for coolingwafers 5, another wafer accommodating chamber 30 may be used fortransferring wafers 5 to the reaction chamber 70, thereby saving time.Also, two kinds of the wafer accommodating chambers 30, one for incomingwafers 5 and the other for outgoing wafers 5, may be separatelyprovided. This allows two kinds of the wafer accommodating chambers 30to be alternately used, thereby saving time. Further, a certain waferaccommodating chamber 30 may be used for monitor wafers, and anotherwafer accommodating chamber 30 may be used for process wafers which willbecome actual products.

Since the plurality of wafer accommodating chambers 30 are disposed invertical layers on the wall 54 of the wafer transfer chamber 50, thearea occupied by the wafer accommodating chambers 30 within a clean roomcan be reduced. Also, the number of sides of the wafer transfer chamber50 can be reduced thereby to reduce the size of the wafer transferchamber 50, resulting in a reduction in the area occupied by the wafertransfer chamber 50. Thus, the semiconductor wafer processing apparatus1 occupies less area within the clean room. Further, the cost ofmanufacture of the wafer transfer chamber 50 is reduced.

Since the gate valve 92 is disposed between the wafer transfer chamber50 and the wafer accommodating chamber 30, the pressure of the waferaccommodating chamber 30 can be restored to atmospheric pressure whilethe wafer transfer chamber 50 is maintained under reduced pressure.Therefore, each wafer 5 contained in the wafer accommodating chamber 30cools naturally while the pressure of the wafer accommodating chamber 30is being restored to atmospheric pressure, so that the temperature ofeach wafer 5 is lowered to a sufficient level before the wafer 5 leavesthe wafer accommodating chamber 30. Accordingly, even when the wafers 5are subsequently taken out into atmospheric environment, the wafers 5are prevented from being oxidized or contaminated by atmosphericenvironment. In this manner, a step of restoring pressure to atmosphericpressure and a step of cooling wafers 5 are simultaneously performedwithin the wafer accommodating chamber 30, and subsequently the cooledwafers 5 are transferred under atmospheric pressure to the cassette 10.The cassette 10 which contains the wafers 5 is then delivered out fromthe wafer processing apparatus 1.

In the present embodiment, the cassette transfer and wafer transferdevice 20, not the wafer-transfer vacuum robot 60 disposed within thewafer transfer chamber 50, is used for transferring wafers 5 between thewafer accommodating chamber 30 and the cassettes 10, thereby reducingtime required for transferring wafers 5. Also, in the presentembodiment, since the cassette transfer and wafer transfer device 20 isdisposed within the atmospheric pressure section 200, the cassettetransfer and wafer transfer device 20 can be made simpler in structureas compared with the case where it is disposed in a vacuum atmosphere.

The wafer transfer chamber 50 is adapted to be evacuated via the exhaustpipes 84 and 81. Also, the plurality of reaction chambers 70, the wafertransfer chamber 50, and the plurality of wafer accommodating chambers30 are adapted to be evacuated independently of one another.

Since the wafer transfer chamber 50 and the wafer accommodating chamber30 can be depressurized, the oxygen concentration therein can be reducedto an ultimate level, thereby suppressing oxidation of wafers 5 in thewafer transfer chamber 50 and in the wafer accommodating chamber 30.

Since the reaction chambers 70 can be independently evacuated, each ofthe reaction chambers 70 can function as a reaction chamber forprocessing wafers 5 under reduced pressure. Further, after the reactionchamber 70 is depressurized, the atmosphere therein can be replaced witha predetermined atmospheric gas, thereby establishing a highly puregaseous atmosphere therein.

In the present embodiment, the plurality of reaction chambers 70 are allused for processing wafers 5 under reduced pressure. However, theplurality of reaction chambers 70 may all be used for processing wafers5 under atmospheric pressure, or at least one of these reaction chambers70 may be used for processing wafers 5 under atmospheric pressure whilethe remaining reaction chambers 70 may be used for processing wafers 5under reduced pressure.

The wafer-transfer vacuum robot 60 is disposed within the wafer transferchamber 50. FIGS. 5A and 5B are schematic perspective views forexplaining the wafer-transfer vacuum robot 60. The wafer-transfer vacuumrobot 60 is an articulated robot and is composed of arms 63, 65, and 67,each swingable in a corresponding horizontal plane, and rotational axles62, 64, and 66 for swinging the respective arms. The robot 60 alsoinclude a two-axis driving unit 69 for rotating the rotational axle 62,a gear mechanism (not shown) for transmitting the rotation of therotational axle 62 to the rotational axles 64 and 66, and a driving unitcontainer 61 for accommodating the driving unit 69. The tip of the arm67 is formed into a wafer mounting arm 68 for mounting wafers 5 thereon.As the rotational axle 62 rotates, the arms 63, 65, and 67 swing in thecorresponding horizontal planes, thereby moving wafers 5 mounted on thewafer mounting arm 68 in a horizontal direction.

Two sets of the arm 67 and the wafer mounting arm 68 are disposed. Thedistance between the wafer mounting arms 68 is made equal to the pitchof the wafer supporting grooves 45 of the wafer holder 40 and the pitchof wafers 5 mounted in the wafer boat 75 contained in the reactionchamber 70. Accordingly, there is no need for changing the pitch ofwafers 5 on the way of transfer between the wafer holder 40 and thereaction chamber 70. Thus, although the wafer-transfer vacuum robot 60can transfer two wafers 5 at one time using the two wafer mounting arms68, the structure of the wafer-transfer vacuum robot 60 can besimplified, and contamination of a vacuum atmosphere can be prevented.Further, since two wafers 5 can be transferred at one time, the wafertransferring efficiency increases.

The driving unit container 61 has a hermetically sealed structure. Sincethe driving unit is accommodated in this hermetically sealed container61, the atmosphere within the wafer transfer chamber 50 can bemaintained clean.

A projecting section 52 whose shape corresponds to that of the drivingunit container 61 is projected from a bottom 56 of the wafer transferchamber 50 so as to accommodate the driving unit container 61. Since inorder to accommodate the driving unit container 61, only the projectingsection 52 is projected from the wafer transfer chamber 50, the volumeof the wafer transfer chamber 50 can be reduced, thereby reducing timerequired for evacuating the wafer transfer chamber 50.

A through-hole 57 is formed in the bottom 56 of the wafer transferchamber 50. A screw shaft 561 is vertically disposed outside and underthe wafer transfer chamber 50. A motor 566 is disposed on the upperportion of the screw shaft 561 so as to rotate the screw shaft 561. Anut 565 is attached to the screw shaft 561, thereby forming a ball screwby the nut 565 and the screw shaft 561. A lifting base 564 is fixed tothe nut 565. One end of a support bar 563 for supporting thewafer-transfer vacuum robot 60 is fixed onto the lifting base 564 suchthat the support bar 563 stands upright on the lifting base 564. Anotherend of the support bar 563 is fixed to the upper end portion of thedriving unit container 61 of the wafer-transfer vacuum robot 60. Thesupport bar 563 is made of stainless steel. Metal bellows 562 isdisposed so as to cover the support bar 563 and such that one end of thebellows 562 is fixed in a hermetically sealed manner onto the bottom 56so as to surround the through-hole 57 while the other end of the bellows562 is fixed in a hermetically sealed manner onto the top face of thelifting base 564.

As the screw shaft 561 is rotated by the motor 566, the nut 565 goes upand down, and the lifting base 564 fixed to the nut 565 goes up and downaccordingly. As the lifting base 564 goes up and down, the support bar563, which is fixed perpendicularly onto the lifting base 564, forsupporting the wafer-transfer vacuum robot 60 goes up and down, and thewafer-transfer vacuum robot 60 attached to the support bar 563 goes upand down accordingly.

The present embodiment uses the ball screw 560 composed of screw shaft561 and the nut 565, thereby reducing friction and increasing mechanicalefficiency. Since the ball screw 560 is disposed outside the wafertransfer chamber 50, the interior of the wafer transfer chamber 50 canbe prevented from being contaminated, thereby preventing wafers 5 frombeing contaminated. Further, since the ball screw 560 is located underthe bottom 56 of the wafer transfer chamber 50, the interior of thewafer transfer chamber 50 can be prevented from being contaminated withparticles generated from the bellows 562.

Since the wafer-transfer vacuum robot 60 is mechanically connected tothe lifting base 564 via the rigid stainless-steel support bar 563 forsupporting the wafer-transfer vacuum robot 60, the wafer-transfer vacuumrobot 60 goes up and down reliably as the lifting base 564 goes up anddown.

The support bar 563 for supporting the wafer-transfer vacuum robot 60 iscovered with the bellows 562 such that one end of the bellows 562 isfixed in a hermetically sealed manner onto the bottom 56 of the wafertransfer chamber 50 so as to surround the through-hole 57 while theother end of the bellows 562 is fixed in a hermetically sealed manneronto the top face of the lifting base 564. The bellows 562, therefore,maintains reliably the wafer transfer chamber 50 in a hermeticallysealed state, thereby allowing the wafer transfer chamber 50 to beevacuated. Also, since the movement of the support bar 563 forsupporting the wafer-transfer vacuum robot 60 is isolated from themaintenance of hermetic seal, the support bar 563 moves smoothly andreliably.

Further, since an end of the support bar 563 for supporting thewafer-transfer vacuum robot 60 is fixed onto the upper end portion ofthe driving unit container 61 of the wafer-transfer vacuum robot 60, theheight of the wafer transfer chamber 50 can be reduced, and accordinglythe height of the entire semiconductor wafer processing apparatus 1 canbe reduced.

The entire semiconductor wafer processing apparatus 1 is accommodated ina housing 900. A filter (not shown) and a fan (not shown) are disposedon the ceiling of the housing 900 corresponding to the front section 100so as to produce a downflow into the housing 900. Cassette shelves 11for mounting the cassettes 10 thereon are disposed within and attachedto the housing 900. The cassette shelves 11 are disposed substantiallyopposite to the wafer transfer chamber 50 with respect to the waferaccommodating chamber 30. Three cassette shelves 11 are arranged in eachof horizontal planes located at two different positions in the verticaldirection. That is, a first set of three cassette shelves 11 arearranged at the same height, and a second set of three cassette shelves11 are disposed above the first set of cassette shelves 11. As a resultof providing the cassette shelves 11 within the housing 900, thesurfaces of wafers 5 carried in the cassette 10 can be maintained clean.Also, since a plurality of cassettes 11 are provided, cassettes 11 canbe arranged for each of a plurality of kinds of processing. Moreover, itis possible to dispose a cassette which holds wafers for monitoring anda cassette which holds dummy wafers.

A cassette IN/OUT opening 13 is provided at the lower portion of thefront panel 901 of the housing 900. A cassette stage 12 is disposedwithin the housing 900 at the substantially same height as that of thecassette IN/OUT opening 13. The cassette 10 carried into the housing 900through the cassette IN/OUT opening 13 is temporarily held on thecassette stage 12, and also the cassette 10 which contains the processedwafers 5 is temporarily held on the cassette stage 12 before it isdelivered out from the housing 900.

The cassette stage 12 is located under the cassette shelves 11 so as toprevent the wafers 5 contained in the cassette 10 placed on the cassetteshelf 11 from being affected by particles which enter the housing 900from outside through the cassette IN/OUT opening 13 when the cassette 10enters/leaves the housing 900.

Between the wafer accommodating chamber 30 and the cassette shelves 11is disposed the cassette transfer and wafer transfer device 20 which canload the cassette 10 onto and unload from the cassette shelf 11 andwhich can transfer wafers 5 between the cassette 10 and the waferaccommodating chamber 30. The cassette transfer and wafer transferdevice 20 has a ball screw composed of a screw shaft 29 and a nut (notshown). As the screw shaft 29 rotates, the cassette transfer and wafertransfer device 20 goes up and down accordingly. Since the cassettetransfer and wafer transfer device 20 is provided within the housing900, the surfaces of wafers 5 being transferred thereby can bemaintained clean.

FIG. 6 is a schematic perspective view for explaining the cassettetransfer and wafer transfer device 20.

A cassette transfer device 21 and a wafer transfer device 23 aredisposed on bases 25 and 26 and can independently perform paralleldisplacement in the direction of a corresponding arrow. The cassettetransfer device 21 has a cassette transfer arm 22 and transfers thecassette 10 which is mounted on a cassette holder 27 attached to an endof the cassette transfer arm 22. The wafer transfer device 23 has aplurality of tweezers 24, each carrying wafers 5 by mounting wafers 5thereon.

FIG. 7A is a side view for explaining the pitch changing mechanism ofthe cassette transfer and wafer transfer device, and FIG. 7B is a rearview taken along the line Y--Y in FIG. 7A.

In the present embodiment, the wafer transfer device 23 has fivetweezers 241-245. The tweezer 241 is integral with a block 260. Nuts232, 233, 234, and 235 are fixed to the tweezers 242, 243, 244 and 245,respectively. The nuts 232 and 234 are in screw-engagement with a screwshaft 210, thereby forming ball screws, respectively. The nuts 233 and235 are in screw-engagement with a screw shaft 211, thereby forming ballscrews, respectively. The upper ends of the screw shafts 210 and 211 areconnected to a motor 220 via an unillustrated gear mechanism. The lowerends of the screw shafts 210 and 211 are rotatably supported by theblock 250. Between the block 250 and the block 260 is disposed a nut270, which is in screw-engagement with a screw shaft 280. The nut 270and the screw shaft 280 constitute a ball screw. When the screw shaft280 is rotated, the nut 270 moves in a horizontal direction accordinglyso as to move the tweezers 241-245 rightward and leftward in FIG. 7A.

A thread of a certain pitch is formed in an area 212 of the screw shaft210 in which the nut 232 is engaged with the screw shaft 210, while athread having a pitch double the pitch in the area 212 is formed in anarea 213 of the screw shaft 210 in which the nut 233 is engaged with thescrew shaft 210. A thread having a pitch three times the pitch in thearea 212 is formed in an area 214 of the screw shaft 210 in which thenut 234 is engaged with the screw shaft 210, while a thread having apitch four times the pitch in the area 212 is formed in an area 215 ofthe screw shaft 210 in which the nut 235 is engaged with the screw shaft210. No relative movement in the vertical direction occurs between theblocks 250 and 260. When the screw shafts 210 and 211 are rotated by themotor 220, the nut 232 is raised by a predetermined distance relative tothe blocks 250 and 260, which are stationary. Further, the nut 233 israised over a distance double the distance over which the nut 232 israised, the nut 234 is raised over a distance three times the distanceover which the nut 232 is raised, and the nut 235 is raised over adistance four times the distance over which the nut 232 is raised. As aresult, the tweezer 241 is not raised, the tweezer 242 is raised over apredetermined distance, the tweezer 243 is raised over a distance doublethe raised distance of the tweezer 242, the tweezer 244 is raised over adistance three times the raised distance of the tweezer 242, and thetweezer 245 is raised over a distance four times the raised distance ofthe tweezer 242. As a result, the pitch of the tweezers 241-245 can bechanged uniformly.

FIG. 8 is a schematic cross-sectional view for explaining the operationof transferring wafers 5 in the semiconductor processing apparatus 1according to the first embodiment. The operation for transferring andprocessing wafers 5 will be described with reference to FIGS. 2-8.

The cassette 10 which has been carried into the housing 900 of thesemiconductor wafer processing device 1 through the cassette IN/OUTopening 13 is first placed on the cassette stage 12. Then, the cassette10 is transferred onto the cassette holder 27 attached to the end of thecassette transfer arm 22 of the cassette transfer and wafer transferdevice 20. The cassette transfer and wafer transfer device 20 carriesthe cassette 10 to the upper portion of the housing 900 and thentransfers it onto the cassette shelf 11. Next, the cassette transferdevice 21 moves leftward, and the wafer transfer device 23 then movesrightward so that the wafers 5 in the cassette 10 are mounted onto thetweezers 24. At this time, the pitch of the tweezers 24 is set to beequal to the pitch of the grooves of the cassette 10.

Subsequently, the wafer transfer device 23 is retracted and rotated by180 degrees. Next, the pitch of the tweezers 24 is changed such that thepitch of the tweezers 24 becomes equal to the pitch of the wafersupporting grooves 45 of the wafer holder 40. Subsequently, the tweezers24 are moved leftward so as to load wafers 5 into wafer holder 40 withinthe wafer accommodating chamber 30. In the present embodiment, fivewafers 5 are transferred at once from the cassettes 10 to the waferholder 40 by the cassette transfer and wafer transfer device 20. Whenthe wafers 5 are transferred into the wafer accommodating chamber 30 bythe cassette transfer and wafer transfer device 20, the gate valve 92 isclosed, while the front door valve 91 is opened.

After the wafer holder 40 in the wafer accommodating chamber 30 isloaded with the wafers 5, the front door valve 91 is closed, and thewafer accommodating chamber 30 is evacuated.

After the evacuation, the gate valve 92 is opened. The wafer transferchamber 50 has been evacuated in advance.

Subsequently, the wafers 5 are held by the wafer mounting arms 68 of thewafer-transfer vacuum robot 60 in the evacuated wafer transfer chamber50, and are transferred from the wafer holder 40 within the waferaccommodating chamber 30 to the wafer boat 75 within the reactionchamber 70. At this time, the gate valve 93 is open, and the reactionchamber 70 has already been evacuated. Since the pitch of the wafersupporting grooves 45 of the wafer holder 40 is equal to the pitch ofthe wafers 5 loaded on the wafer boat 75, the pitch of the wafermounting arms 68 of the wafer-transfer vacuum robot 60 is not changedand is maintained constant. In the present embodiment, two wafers aretransferred at a time from the wafer holder 40 to the wafer boat 75 bythe wafer-transfer vacuum robot 60.

After the transfer operation, the gate valve 93 is closed, and apredetermined atmosphere is created in the reaction chamber 70.Subsequently, the two wafers 5 loaded onto the wafer boat 75 in thereaction chamber 70 are simultaneously subjected to a predeterminedprocessing such as film forming processing.

Upon completion of the predetermined processing, the reaction chamber 70is evacuated, and the gate valve 93 is opened. The wafers 5 aretransferred to the wafer holder 40 within the evacuated waferaccommodating chamber 30 by the wafer-transfer vacuum robot 60. At thistime, the pitch of the wafer carrying arms 68 of the wafer-transfervacuum robot 60 is not changed and is maintained constant. Two wafersare transferred at a time.

Subsequently, the gate valve 92 is closed, and atmospheric pressure iscreated in the wafer accommodating chamber 30 using nitride or the like,and the wafers 5 are cooled until the temperature of each wafer reachesa predetermined temperature.

Subsequently, the front door valve 91 is opened, and the wafers 5 aretransferred into the cassette 10 by the wafer transfer device 23 of thecassette transfer and wafer transfer device 20. At this time, the pitchof the tweezers 24 is changed from a pitch corresponding to the pitch ofthe wafer supporting grooves 45 of the wafer holder 40 to a pitchcorresponding to the pitch of the grooves of the cassette 10.

When a predetermined number of wafers 5 are transferred into thecassette 10, the cassette 10 is transferred to the cassette stage 12 bythe cassette transfer device 21. The cassette 10 is then taken outthrough the cassette IN/OUT opening 13.

As described above, since two wafers are simultaneously treated in thereaction chamber 70, wafers can be processed with an improvedefficiency. Since the pitch of the wafer supporting grooves 45 of thewafer holder 40 is equal to the pitch of wafers held on the wafer boat75, it is not necessary to change the pitch of wafer mounting arms 68 ofthe wafer-transfer vacuum robot 60. Therefore, the structure of thewafer-transfer vacuum robot 60 can be simplified and the vacuum createdin the wafer transfer chamber 50 is prevented from being contaminated.Since two wafers 5 can be transferred at a time, the efficiency of wafertransfer can be increased.

Although the pitch of wafers 5 is changed by the cassette transfer andwafer transfer device 20, the cassette transfer and wafer transferdevice 20 is used under the atmospheric pressure. Therefore, even whenthe pitch of wafers 5 is changed, the cassette transfer and wafertransfer device 20 can have a simpler structure and can be manufacturedat lower cost compared to the case in which the pitch of wafers 5 ischanged in a vacuum. In addition, the generation of particles can besuppressed.

As described above, the pitch of wafers 5 is changed under theatmospheric pressure and is fixed under the reduced pressure, and aplurality of wafers 5 are transferred at a time. Therefore, themanufacturing cost of the transfer apparatus can be decreased, and thesize of the transfer apparatus is prevented from increasing. Inaddition, the generation of particles is suppressed, so that wafers 5can be transferred in a clean environment. Moreover, simultaneoustransfer of a plurality of wafers 5 improves the throughput, and thecapability of changing the pitch of wafers 5 makes it possible to changethe pitch of wafers 5 so as to guarantee that wafer processing isperformed highly accurately in the reaction chamber 70.

In the present embodiment, the walls 53 and 54 of the wafer transferchamber 50 are opposed to each other so as to arrange on a substantiallystraight line the reaction chamber 70, the wafer transfer chamber 50,and the wafer accommodating chamber 30, and the wafer transfer chamber50 has a rectangular shape as viewed from above. As the wafer transferchamber 50 has a rectangular shape, the size of the wafer transferchamber 50 can be reduced, and the area occupied by the wafer transferchamber 50 can be reduced accordingly. Thus, the semiconductor waferprocessing apparatus 1 occupies less area within a clean room. Byadopting the rectangular shape, the cost of manufacture of the wafertransfer chamber 50 is reduced, and a required maintenance space is alsoreduced. Further, the distance over which a connection is made betweenthe wafer transfer chamber 50 and another wafer transfer chamber or thelike can be reduced. This allows the wafers 5 to be readily transferredbetween the wafer transfer chamber 50 and another wafer transfer chamberor the like without providing a wafer transfer device at a connectingsection therebetween; thus the semiconductor wafer processing apparatus1 can accordingly be made simpler in structure and manufactured at lowercost. A plurality of semiconductor wafer processing units, each havingthe structure such that the reaction chamber 70, the wafer transferchamber 50, and the wafer accommodating chamber 30 are arranged on asubstantially straight line, can be readily arranged in parallel so thatthey occupy less area.

Second Embodiment:

FIG. 9 is a cross-sectional view for explaining a semiconductor waferprocessing apparatus according to a second embodiment of the presentinvention. The semiconductor wafer processing apparatus 1 of the presentembodiment is the same as that of the first embodiment except that: thereactions chambers 70, the wafer transfer chamber 50, and the waferaccommodating chambers 30 are located at the lower portion of thehousing 900; and the wafer-transfer vacuum robot 60, and the screw shaft561 and the like for lifting/lowering the wafer-transfer vacuum robot 60are located at the upper portion of the housing 900.

Third Embodiment:

FIG. 10 is a cross-sectional view for explaining a semiconductor waferprocessing apparatus according to a third embodiment of the presentinvention.

According to the present embodiment, six reaction chambers 70 arearranged in the vertical direction on the wall 53 of the wafer transferchamber 50, and four wafer accommodating chambers 30 are arranged in thevertical direction on the wall 54 of the wafer transfer chamber 50.Because of an increase in the number of the reaction chambers 70 as wellas the wafer accommodating chambers 30, the height of the wafer chamber50 is increased accordingly. In order to accommodate this many reactionchambers 70 and wafer accommodating chambers 30 within the housing 900,the projecting section 52 of the wafer transfer chamber 50, the screwshaft 561, the bellows 562, and the support bar 563 for supporting thewafer-transfer vacuum robot 60 are partially projected from the housing900. Since these projecting portions can be projected downward from thefloor of a clean room, the height of the wafer transfer chamber 50 canbe increased, thereby allowing more reaction chambers 70 as well as morewafer accommodating chambers 30 to be arranged in the verticaldirection. Thus, more wafers 5 can be processed within less area.

Fourth Embodiment:

FIG. 11 is a plan view for explaining a semiconductor wafer processingapparatus according to a fourth embodiment of the present invention.

In the present embodiment, semiconductor wafer processing units 2 and 2'are disposed in parallel, the unit 2 (2') having the structure such thatthe reaction chamber 70 (70'), the wafer transfer chamber 50 (50'), thewafer accommodating chamber 30 (30'), the cassette transfer and wafertransfer device 20 (20'), and the cassette shelf 10 (10') are arrangedon a substantially straight line. The semiconductor wafer processingunits 2 and 2' each having such a structure can be readily disposed inparallel, thereby reducing the area occupied by the entire apparatuscomposed of the units 2 and 2'.

The wafer transfer chamber 50 (50') has a rectangular shape as viewedfrom above. Accordingly, the distance over which a connection is madebetween the wafer transfer chamber 50 and the wafer transfer chamber 50'can be reduced. This allows a wafer to be readily transferred betweenthe wafer transfer chamber 50 and the wafer transfer chamber 50' withoutproviding a wafer transfer device in an intermediate wafer transferchamber 90, which serves as a connecting section between the chambers 50and 50'. Thus, the semiconductor wafer processing apparatus 1 canaccordingly be made simpler in structure and manufactured at lower cost.The intermediate wafer holding chamber 90 can also be used as a coolingchamber for cooling a wafer or as a preheating chamber for preheating awafer.

A space located between the reaction chamber 70 and the reaction chamber70' is large enough for use as a common maintenance space 3 for thesemiconductor wafer processing units 2 and 2'.

Fifth Embodiment:

FIG. 12 is a plan view for explaining a semiconductor wafer processingapparatus according to a fifth embodiment of the present invention.

In the present embodiment, a semiconductor wafer processing unit 6according to the present invention, which has the structure such thatthe reaction chamber 70, the wafer transfer chamber 50, the waferaccommodating chamber 30, the cassette transfer and wafer transferdevice 20, and the cassette shelf 10 are arranged on a substantiallystraight line, is connected to a semiconductor wafer processing unit 7,which includes a wafer transfer chamber 150 which is hexagon-shaped asviewed from above and on side walls of which cassette chambers 131 and132, reaction chambers 171 and 172, and a wafer cooling chamber 142 areprovided.

Since the wafer transfer chamber 50 is rectangle-shaped, it can bereadily connected via the wall 51 thereof to a semiconductor waferprocessing unit having a different shape.

Also, in the present embodiment, the distance over which a connection ismade between the wafer transfer chamber 50 and the wafer transferchamber 150 can be reduced. This allows a wafer to be readilytransferred between the wafer transfer chamber 50 and the wafer transferchamber 150 without providing a wafer transfer device in an intermediatewafer transfer chamber 90, which serves as a connecting section betweenthe chambers 50 and 150. Thus, the semiconductor wafer processingapparatus as a whole can accordingly be made simpler in structure andmanufactured at lower cost. The intermediate wafer transfer chamber 90can also be used as a cooling chamber for cooling a wafer or as apreheating chamber for preheating a wafer.

Sixth Embodiment:

FIG. 13 is a plan view for explaining a semiconductor wafer processingapparatus according to a sixth embodiment of the present invention.

In the present embodiment, a wafer transfer chamber 55 is octagon-shapedas viewed from above, and the reaction chambers 70 are provided inlayers on each of the seven side walls of the wafer transfer chamber 55.

Seventh Embodiment:

FIG. 14 is a plan view for explaining a semiconductor wafer processingapparatus according to a seventh embodiment of the present invention.

In the present embodiment, the wafer transfer chamber 55 of FIG. 13 fromwhich reaction chambers 70a are removed is connected via an intermediatewafer transfer chamber 90 to the wafer transfer chamber 55 of FIG. 13from which reaction chambers 70b are removed. The intermediate wafertransfer chamber 90 can also be used as a cooling chamber for cooling awafer or as a preheating chamber for preheating a wafer.

What is claimed is:
 1. A substrate processing apparatus, comprising:asubstrate transfer chamber which can be depressurized; a plurality ofsubstrate processing chambers disposed on a first side wall of saidsubstrate transfer chamber, said plurality of the substrate processingchambers being stacked in the vertical direction; a plurality of firstvalves, each being disposed between each of said substrate processingchambers and said substrate transfer chamber, and each of said pluralityof the first valves being capable of providing hermetic vacuum isolationbetween each of said substrate processing chambers and said substratetransfer chamber when closed and allowing a substrate to passtherethrough when opened; a substrate accommodating chamber disposed ona second side wall of said substrate transfer chamber; a substratetransfer device disposed within said substrate transfer chamber andbeing capable of transferring said substrate under reduced pressurebetween said substrate processing chambers and said substrateaccommodating chamber; an elevating device disposed outside saidsubstrate transfer chamber and comprising a stationary portion and anelevating portion which is vertically movable with respect to saidstationary portion; a rigid connecting member capable of moving througha through-hole formed in a predetermined face of said substrate transferchamber, said rigid connecting member mechanically connecting saidelevating portion and said substrate transfer device through saidthrough-hole; and a sealing member for establishing a hermetic vacuumseal between said predetermined face and said connecting member whichpenetrates through said through-hole.
 2. A substrate processingapparatus as recited in claim 1, wherein said substrate transfer deviceis a substrate transfer device capable of transferring a substrate in ahorizontal direction.
 3. A substrate processing apparatus as recited inclaim 1, wherein said sealing member is formed of an elastic materialand covers said connecting member such that said connecting member canmove within said sealing member and that one end of said sealing memberis connected in a hermetically vacuum-sealed manner to saidpredetermined face of said substrate transfer chamber while the otherend of said sealing member is connected in a hermetically vacuum-sealedmanner to said connecting member.
 4. A substrate processing apparatus asrecited in claim 3, wherein said sealing member is made of bellows.
 5. Asubstrate processing apparatus as recited in claim 1, wherein saidstationary portion is a screw shaft, and said elevating portioncomprises a nut, whereby said screw shaft and said nut constitute a ballscrew.
 6. A substrate processing apparatus as recited in claim 5,wherein said predetermined face of said substrate transfer chamber isthe bottom face of said substrate transfer chamber, and said ball screwis located under said substrate transfer chamber.
 7. A substrateprocessing apparatus as recited in claim 5, wherein said predeterminedface of said substrate transfer chamber is the top face of saidsubstrate transfer chamber, and said ball screw is located above saidsubstrate transfer chamber.
 8. A substrate processing apparatus asrecited in claim 1, wherein said substrate transfer device comprises adriving unit, a substrate transfer unit capable of moving in asubstantially horizontal direction by said driving unit, and a drivingunit container capable of providing hermetic vacuum isolation betweenthe inside and outside of said driving unit container, said driving unitbeing accommodated in said driving unit container.
 9. A substrateprocessing apparatus as recited in claim 8, wherein one end portion ofsaid rigid connecting member is connected to said driving unit containerat the vicinity of an end portion thereof located closer to saidsubstrate transfer unit.
 10. A substrate processing apparatus as recitedin claim 8, wherein said predetermined face of said substrate transferchamber is the bottom face of said substrate transfer chamber, and aprojecting section whose shape corresponds to said driving unitcontainer is projected from the bottom face, such that said projectingsection is capable of accommodating said driving unit container therein.11. A substrate processing apparatus as recited in claim 8, wherein saidpredetermined face of said substrate transfer chamber is the top face ofsaid substrate transfer chamber, and a projecting section whose shapecorresponds to said driving unit container is projected from the topface, such that said projecting section is capable of accommodating saiddriving unit container therein.
 12. A substrate processing apparatus asrecited in claim 1, wherein a second valve is disposed between saidsubstrate accommodating chamber and said substrate transfer chamber,said second valve being capable of providing hermetic vacuum isolationbetween said substrate accommodating chamber and said substrate transferchamber when closed and allowing a substrate to pass therethrough whenopened, thereby allowing said substrate accommodating chamber to bedepressurized independently of said substrate transfer chamber.
 13. Asubstrate processing apparatus as recited in claim 12, furthercomprising an atmospheric pressure section located outside the substratetransfer chamber and said substrate accommodating chamber, and a thirdvalve disposed between said substrate accommodating chamber and saidatmospheric pressure section, said third valve being capable ofmaintaining said substrate accommodation chamber under vacuum inisolation from said atmospheric pressure section when closed andallowing a substrate to pass therethrough when opened.
 14. A substrateprocessing apparatus as recited in claim 1, further comprising one ormore second substrate accommodating chambers and one or more fourthvalves, said substrate accommodating chamber and said one or more secondsubstrate accommodating chambers being disposed such that said substrateaccommodating chamber and said one or more second substrateaccommodating chambers are vertically arranged on said second side wallof said substrate transfer chamber, said substrate accommodating chamberand said one or more second substrate accommodating chambers beingstacked in the vertical direction, each of said one or more fourthvalves being located between each of said one or more second substrateaccommodating chambers and said substrate transfer chamber and beingcapable of providing hermetic vacuum isolation between each of said oneor more second substrate accommodating chambers and said substratetransfer chamber when closed and allowing a substrate to passtherethrough when opened, whereby said one or more second substrateaccommodating chambers can be depressurized independently of one anotherand each of said one or more second substrate accommodating chambers canbe depressurized independently of said substrate transfer chamber andsaid substrate accommodating chamber.
 15. A substrate processingapparatus as recited in claim 1, further comprising:an atmosphericpressure section located outside the substrate transfer chamber and saidsubstrate accommodating chamber; a cassette holding device locatedwithin said atmospheric pressure section; and a substrate transferdevice located within said atmospheric pressure section and capable oftransferring a substrate between a cassette held by said cassetteholding device and said substrate accommodating chamber.
 16. A substrateprocessing apparatus as recited in claim 15, further comprising ahousing for accommodating said substrate processing chambers, saidsubstrate transfer chamber, said substrate accommodating chamber, saidsubstrate transfer device, and said cassette holding device.
 17. Asubstrate processing apparatus as recited in claim 10, furthercomprising a housing for accommodating at least said substrate transferchamber, said plurality of substrate processing chambers, and saidsubstrate accommodating chamber, wherein at least each part of each ofsaid projecting section of said substrate transfer chamber, saidelevating device and said connecting member is projected from saidhousing.
 18. A substrate processing apparatus as recited in claim 1,further comprising a first substrate holding unit having heatresistance.
 19. A substrate processing apparatus as recited in claim 1,further comprising:a first substrate holding unit, disposed within saidsubstrate accommodating chamber, for holding said substrate; and asecond substrate holding unit, disposed within said substrate processingchamber, for holding said substrate, wherein said second substrateholding unit is capable of holding a plurality of substrates, said firstsubstrate holding unit is capable of holding a plurality of substrates,and the pitch of substrates held by said first substrate holding unit issubstantially identical to that of substrates held by said secondsubstrate holding unit.
 20. A substrate processing apparatus as recitedin claim 15, further comprising:a first substrate holding unit, disposedwithin said substrate accommodating chamber, for holding said substrate;and a second substrate holding unit, disposed within said substrateprocessing chamber, for holding said substrate, wherein said secondsubstrate holding unit is capable of holding a plurality of substrates,said first substrate holding unit is capable of holding a plurality ofsubstrates, and the pitch of substrates held by said first substrateholding unit is substantially identical to that of substrates held bysaid second substrate holding unit, and wherein said substrate transferdevice is capable of transferring a plurality of substrates at one timeand changing the pitch of said substrates.
 21. A substrate processingapparatus as recited in claim 19, wherein said substrate transfer deviceis capable of transferring a plurality of substrates at one time underreduced pressure.
 22. A substrate processing apparatus as recited inclaim 18, wherein said first substrate holding unit is capable ofholding at least twice as many substrates as those to be processed atone time within each of said substrate processing chambers.
 23. Asubstrate processing apparatus as recited in claim 19, wherein saidfirst substrate holding unit is capable of holding at least twice asmany substrates as those to be held by said second substrate holdingunit.
 24. A substrate processing apparatus as recited in claim 1,wherein said first and second side walls of said substrate transferchamber are opposed to each other so as to arrange on a substantiallystraight line said substrate processing chamber, said substrate transferchamber, and said substrate accommodating chamber.
 25. A substrateprocessing apparatus as recited in claim 24, wherein said substratetransfer chamber has a rectangular shape as viewed from above.
 26. Asubstrate processing apparatus as recited in claim 15, wherein saidcassette holding device is located opposite to said substrate transferchamber with respect to said substrate accommodating chamber.